1. Field of the Invention
The present invention relates to optical displays, and, more particularly, to an ultrathin cellular display panel and a method of making an ultrathin cellular display panel.
2. Description of the Background
Optical screens typically use cathode ray tubes (CRTs) for projecting images onto the screen. The standard screen has a width to height ratio of 4:3 with 525 vertical lines of resolution. An electron beam is scanned both horizontally and vertically across the screen to form a number of pixels which collectively form the image.
Conventional cathode ray tubes have a practical limit in size, and are relatively deep to accommodate the required electron gun. Larger screens are available which typically include various forms of image projection. However, such screens have various viewing shortcomings, including limited viewing angle, resolution, brightness, and contrast, and such screens are typically relatively cumbersome in weight and shape. Furthermore, it is desirable for screens of any size to appear black when not illuminated, in order to improve viewing contrast. However, it is impossible for direct view CRTs to actually be black because they utilize phosphors to form images, and those phosphors are non-black.
Optical panels may be made, for example, by stacking waveguides. Such a panel may be thin in its depth compared to its height and width, and the cladding of the waveguides may be made black to increase the black surface area, but such a panel may also experience limitations in perceived brightness, due to the total internal reflection of light within each waveguide being controlled only in the vertical axis. Further, the presence of black cladding in only one direction may decrease the relative blackness, and thus the contrast, of the screen.
Therefore, the need exists for an optical panel which possesses the advantages corresponding to a stacked waveguide panel, and which does not experience a decrease in brightness or a decrease in contrast over conventional screens.
The present invention is directed to an ultrathin cellular optical panel. The optical panel includes a plurality of optical waveguides, wherein each optical waveguide is formed of a mesh material surrounding an optically clear core. One end of each core of each cell forms an inlet for the cell, and an opposite end of each core of each cell forms an outlet for the cell, and the plurality of inlets form an inlet face for the optical panel, and the plurality of outlets form an outlet face for the optical panel. The optical panel further includes a light generator that generates light incident on the inlet face. Each cell internally reflects the light incoming at the inlet of the cell to the outlet of the cell. The optical panel may additionally include a light redirecting coupling layer parallel to the inlet face that redirects light to couple the light into the inlet of each cell. Further, the optical panel may include a diffusing layer that spreads light exiting the outlet face to the desired viewing angle.
The present invention is also directed to a method of displaying light using an ultrathin cellular display panel. The method includes the steps of providing a plurality of optical waveguides, wherein each cell is formed of a mesh material surrounding an optical core, passing the light substantially perpendicularly to an inlet of the core of each cell, and displaying the light at an outlet of each cell opposite the inlet of each cell, wherein the light at the plurality of outlets forms an image. The method may additionally include the steps of positioning the inlets of each of the mesh screen cells proximate to a light redirecting coupling layer, wherein the light redirecting coupling layer redirects light incident at a substantially acute angle to each inlet into light incident substantially perpendicular to each inlet, and optionally inserting a bond material, such as an adhesive, liquid, or gel, having a higher index of refraction than the mesh material between the mesh screen cells and the light redirecting coupling layer. Further, the method may include the steps of positioning a diffusing layer proximate to the outlets of each of the mesh screen cells, wherein the diffusing layer diffuses the light exiting the plurality of outlets to form the image, and optionally inserting a bond material, such as a transparent adhesive, liquid, or gel, having a similar or identical index of refraction than the optically transmissive cell optical cores between the mesh screen and the diffusing layer.
The present invention solves problems experienced in the prior art, such as the required use of expensive and cumbersome projection equipment, and the great depth of optical panels requiring such projection equipment, due to the provision of total internal reflection of light within each optical waveguide in both the vertical and horizontal directions, thereby improving panel perceived brightness and contrast while maintaining the minimized depth advantages which correspond to a stacked waveguide panel.